import java.io.IOException;
import java.net.DatagramPacket;
import java.net.DatagramSocket;
import java.net.SocketException;

public class TestUdpServer {
    private DatagramSocket socket = null;
    public TestUdpServer(int port) throws SocketException {
        socket = new DatagramSocket(port);
    }

    public void start() throws IOException {
        System.out.println("服务器启动");
        while (true){
            DatagramPacket requestPacket = new DatagramPacket(new byte[4096],4096);

            socket.receive(requestPacket);
            String request = new String(requestPacket.getData(),0,requestPacket.getLength());
            String response = this.process(request);
            DatagramPacket responsePacket = new DatagramPacket(response.getBytes(),0,response.getBytes().length,
                    requestPacket.getSocketAddress());
            socket.send(responsePacket);

            System.out.printf("[%s:%d] req=%s resp=%s\n",requestPacket.getAddress(),requestPacket.getPort(),
                    request,response);
        }
    }

    public String process(String response){
        return response;
    }

    public static void main(String[] args) throws IOException {
        TestUdpServer testUdpServer = new TestUdpServer(9090);
        testUdpServer.start();
    }
}
